Render in 3D audio for YouTube
It's rather simple as to do this, also, for free :)

Thanks to @3DSinghVFX for the answer in a comment.


  During audio rendering, first select audio container (e.g. mp3) then select the "split channel" option which will generate six tracks for 5:1 setup. Then you can mix these tracks with the help of some Ambisonics plugin to generate ACN/SN3D format.


Add all the tracks into a DAW (I'm using Reaper), and enable the WigAmbiRemap JS Effect. Set the Outgoing Amb Normalisation to SN3D and Outgoing Channel Ordering to ACN. Then render to a file with 4 channels.

Then, render the video and "glue" them together with ffmpeg.

Use this in the terminal (CMD or Bash will do, ffmpeg must be installed)

ffmpeg -loop 1 -i video.mov -i ambiX.wav -map 1:a -map 0:v -c:a copy -channel_layout 4.0 -c:v libx264 -b:v 40000k -bufsize 40000k -shortest output.mov


You can change the following:

video.mov can be a .mov file or image file, and represents the video.
ambiX.wav is the 4-channel B360 Ambisonic file.
output.mov is the output file.

After that, pop it through the metadata injector (Making sure you check the 1st and 3rd checkbox, 2nd is optional) and you're done! Just upload it to your site of choice.

Source: YouTube, Ambisonics, and VR